There you are, rocking out to your favorite rock song, drumming your fingers to the guitar riff… or maybe you are 30 minutes into an important phone call, the other person waiting for your reply… or you’re working away on your laptop, caught up in the middle of something urgent. You’re doing something important. That’s always when it happens. The batteries die. In the blink of an eye a digital nightmare begins. It takes just a blip of a second but in that time unsaved work is lost. Calls are missed. Songs interrupted. It’s something that’s happened to us all, a consequence of our digitally connected era. And it is something inventors and engineers have yet to find a solution for. But they are trying.

In Apple’s Cupertino research labs, one idea being explored is small scale solar. In fact, according to reports on the Macrumors website Apple has even filed a patent that aims to harness solar power to fuel future generations of portable devices (iPods, iPhones, Macbook’s etc).

That begs the questions: Will there be a solar iPod? Or a powerful Macbook that makes its own power?

The safe answer is not anytime soon. For one thing, there’s no guarantee a patented invention will ever be commercialized. Companies from Apple to IBM and Microsoft to Zenith hold volumes of patented Intellectual Property that is locked away, unlikely to ever reach a consumer’s wish list. It’s the “research” aspect of R&D; and that’s likely what Apple is doing – experimenting.

For years, decades, the electronics Industry has been interested in ways to make a product less dependent on batteries. Solar energy is abundant, free and recurring. Apple’s interest is no surprise. But there are reasons solar solutions haven’t leapt from antiquated solar calculators to newer products. There are technological explanations. It’s partly an issue of size and scale that still remains.

The lack of solar powered products draws to a simple equation: the more power a device needs, the larger the solar cell supporting it will need to be. Today, devices are growing smaller, not bigger. At the same time, their power demands are moving in the opposite direction. They’re growing. That creates an inherent conflict. The geographic constraint of a cell phone’s (or laptop computer’s) small scale rarely leaves enough exposed free space (surface area) to house solar panels and related components capable of generating sufficient power to recharge a battery or otherwise be worth inclusion.

Apple’s experimental solution, which borrows from a prior patent filed by Motorola, is to put the solar cell behind the screen in a stacked formation. On top would be the touch screen layer, then the LCD display, then the solar panel. It becomes kind of like a skyscraper building upward to maximize real estate. The same space occupied by the screen can do double or even triple duty (with a touch screen) at the cost of just a few millimeters of extra thickness to the device.

The challenge, however, is light transmission. Like the skyscraper analogy, while the top level will get plenty of sun, each subsequent lower floor may be shadowed from above and get less. Layered on the bottom of a stack, it’s possible the solar panel, hindered by light absorption above, won’t even receive enough light to be effective.

And even supposing light does pass through sufficiently to the solar panel? The other question is total power. Is the surface area large enough, or the solar panel efficient enough at converting energy, that just a few inches in size generate enough energy to power the device (or fully charge a battery) in the first place?

For now, the answer is it’s probably not. Despite advances in solar technology and tremendous current investment in the green-tech space, today’s technology just isn’t efficient enough. Far more energy is reflected away than is harnessed. That will change, eventually. Panels will become more efficient. They’ll require less sun exposure; maybe even drawing power off the infrared light of the evenings. It’s all the basis for the experiments. It’s forward thinking.

Apple is not alone in these processes either. A few months ago, Vodaphone announced plans for solar powered chargers. Other consumer products makers are similarly exploring auxiliary solar powered chargers. Brunton, as one example, is currently offering a thin rollout panel the size of a small towel that can be used to power a host of different products. These SolarRolls as they’re called have gotten great reviews for use in expedition travel and remote locations (Climbing Everest, Kayaking the Amazon, etc). Compared to the prospect of a solar panel integrated into an iPhone though? For that, they’re bulky and awkward not to mention expensive (SolarRolls cost $200-$300). But that’s where technology is today.

In other Apple News: Kleiner Perkins iPhone specific “iFund” investment initiative has reportedly chosen the first two companies it will invest in. The first funding winner is Pelago, the owner of an application called Whrrl which is designed to mix the iPhones mapping abilities with local restaurant and services search.

The second application to get a bit of capital is a product called iControl from iControl Networks. Their software is a home automation program that allows users to remotely control in-house appliances and lights through the phone. The program is intended to be sold by home protection companies as part of a bundled suite of home integration technology.